08/18/2026
25 years ago this week, STS-105 astronauts Daniel Barry and Patrick G. Forrester conducted two spacewalks to build the International Space Station. They also mounted the first Materials International Space Station Experiment (MISSE) packages on the exterior of the station, helping us better understand how the materials we use for space exploration are affected by long-term exposure to space.
For years, MISSE experiments with hundreds of samples of materials and technology mounted on them have been attached to the exterior of the station to see how the various samples hold up to the space environment. In low-Earth orbit, these samples are exposed to extreme temperature swings, solar and charged‑particle radiation, atomic oxygen, micrometeoroids, and the vacuum of space—conditions impossible to fully replicate on here on Earth. By testing everything from coatings and fabrics to solar cells and electronics, MISSE has helped engineers create spacecraft hardware that’s tougher and longer lasting.
See for yourself! On the right you can see how the samples on one of the panels installed by the STS-105 astronauts changed over their nearly four years in space.
📸 Left: Astronaut Patrick G. Forrester, works with the newly-installed MISSE on the outside of the station during the second STS-105 extravehicular activity OTD in 2001. Right: Panel from the MISSE-2 experiment before flight vs. after four years in space.
